Elimination of STH morbidity in Zimbabwe: Results of 6 years of deworming intervention for school-age children.

Nicholas Midzi,Isaac Phiri,Gibson Mhlanga,Peter J Diggle,Portia Manangazira,Claudio Fronterre,Masceline J Mutsaka-Makuvaza,Olatunji Johnson,Antonio Montresor,Helton Da Costa Santiago

doi:10.1371/journal.pntd.0008739

Abstract

This paper reports the prevalence and intensity of soil-transmitted helminth (STH) infections measured in Zimbabwe before and after a control intervention based on annual deworming of school-age children (SAC) conducted from 2012 to 2018.In 2010, epidemiological data were collected from 13 195 SAC in 255 randomly selected schools in all districts nationwide using, as diagnostic methods, the Kato–Katz and the formal ether stool concentration technique. At follow up, conducted in 2017, only Kato–Katz was performed; specimens were collected from 13 352 children in 336 schools. The data were evaluated using a geospatial approach. The national prevalence of STH infection in SAC was estimated at 5.8% at baseline, with 0.8% of infections of moderate and heavy intensity. Preventive chemotherapy (PC) targeted all 2.5 million children of school age enrolled in Zimbabwe, with coverage ranging from 49% to 85%. At follow up, national prevalence of STH in SAC was estimated at 0.8%; infections of moderate and heavy intensity almost disappeared (0.1% prevalence). As a result, Zimbabwe can suspend deworming activities in 54 districts and reduce the frequency of PC in the remaining six districts. The total amount of albendazole tablets needed will be approximately 100 000 a year.

Highlights

soil-transmitted helminth (STH) are intestinal parasites that are transmitted by soil contaminated with human excreta
We analysed the impact of 6 years of preventive chemotherapy intervention by the Ministry of Health and Child Care of Zimbabwe (MoHCC) to control STH infections in Zimbabwe
The results are interesting because they demonstrate a complete elimination of infection of moderate heavy intensity

Summary

Introduction

STH are intestinal parasites that are transmitted by soil contaminated with human excreta. Each of the four STH species has distinct characteristics, but they are considered as a single group because of their similar transmission dynamics, diagnosis, and prevention and control measures [1]. More than 2 billion people are estimated to be infected with one or more STH species [2]. The damage to health caused by STH is proportional to the number of worms infecting the host. Infections of light intensity cause minimal associated morbidity, whereas infections of moderate to heavy intensity by large numbers of worms adversely affect nutritional status, impair cognitive processes and are estimated to cause the loss of an estimated 1.2 million disability-adjusted life-years (DALYs) in 2016 [3]

Methods

Results

Discussion

Conclusion